Update GetTargetFilesZipForCustomImagesUpdates zip2zip call

This changes the generation of the target files with oem images to
operate in two passes. 1/ zip2zip is called without any filespec.
2/ oem images are replaced.

This allows to generate the target-files faster (as entries do not
need to be iterated one by one) and removes the need to escape
special file names.

Bug: 269397842
Change-Id: Ic1cf398b90344e01b2f1658079903d45bcc00b46